Revised: Because of the rarity of this item, it will be sold to the highest bid over $1000 US received by midnight (MST) on Tuesday evening January 20. Thank you to all those who have given me an idea of what this item is worth.
This 12.5" paraboloidal primary can be used with either Cassegrain (f/15) or Newton (f/4) secondary, both are included. Originally purchased in 1979, I acquired this set from the original owner in the late 80's, they have never been used and are like new, in the original packaging. Coatings are excellent. Also included is a 9 point primary cell for 15" ID tubing.
The primary is 2.06" thick at outer edge, central perforation is 2.49" diameter. Newton elliptical secondary is 3.1" minor axis. Cassegrain secondary is 4.0" diameter. Primary and Cassegrain secondary both engraved 12-1, 36" separation. A Coulter advertisement in the December 1978 Sky & Telescope states it is aluminized with silicon monoxide over-coating and that it is a 1/16 wave matched set.